A Study of Ifinatamab Deruxtecan in Subjects With Pretreated Advanced or Metastatic Esophageal Squamous Cell Carcinoma (ESCC) (IDeate-Esophageal01)

Plasma pharmacokinetic parameters will be assessed using noncompartmental methods.

Plasma pharmacokinetic parameters will be assessed using noncompartmental methods.

Progression-free survival (PFS) is defined as the time interval from the date of randomization to the first date of disease progression as determined by blinded independent central review (BICR) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 or death due to any cause, whichever occurs first.

Objective response rate (ORR) is defined as the proportion of subjects with a best overall response (BOR) of confirmed complete response (CR) or confirmed partial response (PR) as assessed by BICR per RECIST v1.1.

Duration of response (DoR) is defined as the time from the date of first documentation of objective tumor response (CR or PR), which is subsequently confirmed by BICR assessment, to the first documentation of objective tumor progression (confirmed by BICR) or to death due to any cause, whichever occurs first.

Disease control rate (DCR) is defined as the proportion of participants with a BOR of confirmed CR, confirmed PR, or stable disease (SD) according to RECIST v1.1 and will be determined by BICR assessment review of tumor scans.

A TEAE is defined as an adverse event (AE) with a start or worsening date during the on-treatment period. A serious TEAE is defined as any untoward medical occurrence that at any dose results in death, is life threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is an important medical event, or may jeopardize the participant or may require medical or surgical intervention to prevent one of the other outcomes noted. AESIs will also be assessed. AEs will be coded using MedDRA and will be graded using NCI-CTCAE v5.0.

Anti-drug antibodies (ADAs) will be measured in the plasma using a validated assay.

Plasma pharmacokinetic parameters will be assessed using noncompartmental methods.